Duplex telegraphy system utilizing band compression



June 2, 1953 M, PQTTS 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets-Sheet 1 l'l'l'l'l' FIG. I

- INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. C. POTT$, EXECUTRIX' L. M. POTTS June 2, 1953 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION l7 Sheets-Sheet 2 Original Filed June 18, 1947 INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. 0. POTTS, EXECUTRIX BY Zi ATTORNEY June 2, 1953 M. POTTS 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 l7 Sheets-Sheet 5 Al FIG. 5 F|G.4

INVENTOR LOUIS M. POTTS, DECEASED MARTHA w.c. POTTS, EXECUTRIX BY Z ATTORNEY L. M. POTTS June 2, 1953 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION l7 Sheets-Sheet 4 Original Filed June 18, 1947 INVENTOR LOUIS M. POTTS,DECEASED MARTHA W. 0. POTTS,EXEcuTR|x ATTORNEY L. M. POTTS June 2, 1953 l7 Sheets-Sheet 5 Original Filed June 18, 1947 2 2 2 7.. 2 5 w M 2 3 I .2 2 3 7 II 0 mm 8 .4. k m a .w a m n. S 1 I 7 E l I '8. 6 & I. I O 3 7| 2 l 4 I l 4 v 2 H 3 6 6m E 4 l E. w 5 m N i 4 I I .99 9 wa 5 a I 9 III G .H

I R D T E U S c A E E x S Y W 0.. T E T S T N N T O R E W P m V v T. m n A M W I H W T LR A M June 2, 1953 -rs 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets-Sheet 6 iq 1115 H 208 226 HHHHB INVENTOR LOUIS M. POTT$,DECEA$E D MARTHA w. c. POTTS,EXECUTRIX Fl 6.. l4 ,BY

June 2, 1953 M. POTTS 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June l8, 1947 17 Sheets-Sheet 7 STOP swrl 2 3 4 5 S or SLEEVE SLEEVE MI SLEEVE I42 SLEEVE I95 INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. o. POTT$,EXECUTRIX {2 [Ham ATTORNEY June 2, 1953 M, -rs 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets-Sheet 8 LOUIS m. POTTS,0EcEAsE0 MARTHA w. c. POTTS,EXECUTRIX BY Z1 84AM ATTORNEY June 2, 1953 M. POTTS 2,640,914

DUPLEX TELEGRAPHY SYS-TEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 Y 17 Sheets-Sheet 10 INYENTOR LOUIS M. POTTS,DECEASED MARTHA w. c. POTTS,EXECUTRIX PAM TORNEY L. M. POTTS June 2, 1953 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets-Sheet 11 FIG. 23

In? 610- \I I l I 6 4 n E 6 I. R OF- M mu W Mm 9 1 a N 6 4 2 6 2v 6 3 M. A U 6 6 a 4 2 6 3 I 4 6 1 a 8 6 m 2 5 5 l 7 0 mm M 7 2 \6 m l m 2 T T 6 w B 4 d m. 3 6 6 INVENTOR L. M. POTTS June 2, 1953 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION l7 Sheets-Sheet 12 Original Filed JuneIlS/ 1947 T aRWSMITTER my L FIG.24

INVENTOR LOUIS M. POTT$,DECEA$ED AT TOR NE Y xmhZEm l7 Sheets-Sheet l3 IIHII INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. o. POTTS.EXECUTRIX L. M. POTTS IHII DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION June 2, 1953 Original Filed June 18, 1947 2 ATTORNEY DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets-Sheet 14 RADIO TRANSMITTER \826 324 FIG. 26 w (SCI 808 f 808-2- 568-3 ace-Z 808-5 858-6 808-? am FIG. 26 FIG. 27 FIG. 28

, INVENTOR LOUIS M. POTTS,DEOEASED BY MARTHA V1.0. POTTS, EXECUTRIX W 7ATTORNEY June 2, 1953 L. M. PQTTS 2,640,914

DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 I 17 Shets-Sheet 15 INVENTOR LOUIS u. POTTS DECEASED MARTHA w. c. POTfS EXECUTRIX ATTORNEY- 7 Original Filed Junel8, 1947 June 2, 1953 M. POTTS 2,640,914

I DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION I 17 Sheets-Sheet 1e N n: m 8 1 11f I i |E% J g 1 8 m C D n: L. I J5 LLI 1' e O 4 (/1 f O (D 55 Q N N m 0 3i 7 3 g o:

03 HMI'H 8 T1 \m 10 m m INVENTOR N LOUIS M. POTTS,DECEASED MARTHA W. C. POTTS,ExEcuTR|x B 2 Maw f FATTORNEY L. M. POTTS June 2, 1953 2,640,914 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Original Filed June 18, 1947 17 Sheets+Sheet 17 M m U SC AE Y E 0F- N DS R .N T o E T "u m p 0 C MW M A m OM A L M m Patented June 2, 1953 DUPLEX TELEGRAPHY SYSTEM UTILIZING BAND COMPRESSION Louis M. Potts, deceased, late of Evanston, 111., by Martha W. C. Potts, executrix, Evanston, 111., assignor to Teletype Corporation, Chicago, 1 111., a corporation of Delaware Original application June 18, 1947, Serial No.

755,445, now Patent No. 2,579,612, dated December 25, 1951. Divided and this application November 5, 1948, Serial No. 58,503

16 Claims.

This invention relates to telegraph converter systems and apparatus wherein signal code combinations of one code are converted into signal code combinations of another code and subsequently reconverted into the original signal code combinations.

This application is a division of copending application Serial No. 755,445, filed June 18, 1947, now Pat. No. 2,579,612 granted December 25, 1951.

An object of the present invention is to provide a complete telegraph conversion systemv which includes mechanical apparatus for converting signal code combinations of one code into signal code combinations of a different code, and mechanical apparatus for reconverting said signal code combinations of the difierent code into the original signal code combinations.

A more specific object of the invention is to provide a telegraph conversion system which includes mechanical conversion apparatus for converting five unit start-stop signal code combinations into seven unit radio signal code combinations and mechanical conversion apparatus for reconverting said seven unit radio signal code combination into the original five unit startstop signal code combinations.

A further object of the invention is to provide a mechanical converter unit for converting five unit start-stop signals into seven unit radio signals.

Another object of the invention is to provide a mechanical converter unit for reconverting seven unit radio signals into five unit start-stop signals.

An additional object of the invention is to provide a motor unit for driving both converter units mentioned above.

Another object of the invention is to provide various phasing and orienting devices essential to the maintenance of synchronism between apparatus at remotely located telegraph stations.

A further object of the invention is to provide a simplex radio system with which the converter units and motor unit are adapted to be used.

An additional object of the invention is to provide a two channel one way multiplex systerm in which the groups of signals assigned to one channel are interleaved with the groups of signals assigned to the other channel.

Yet a further, but important, object of the invention is to provide a duplex radio system using a single frequency transmission band.

Further objects and advantages of the invention will appear as the invention is described in detail and restrictions of the scope of the invention should not be implied from the specific recital of the above appearing objects.

According to the present invention, five unit start-stop signals provided by any conventional five unit start-stop transmitter are converted into seven unit radio signals and by means of a radio transmitter are sent to a distant station. At the distant station the seven unit radio signals are received by a radio receiver and reconverted into the original five unit start-stop signals to accordingly operate conventional telegraph recording apparatus. Use of the seven unit radio code with its error detecting feature has proved valuable where transmission of coded messages is required. For example, when coded messages are transmitted in a form such as ABZ, such a group of letters may stand for a phrase, or even a complete sentence containing several words and receipt of a single incorrect character mayrender a message unintelligible or give to the message a meaning different than was intended. Each code combination in the seven unit radio code change contains three marking and four spacing impulses. Any deviation in this fixed ratio of the number of marking impulses to the number of spacing impulses causes the printing of an error indication character. A misselection indicator used for such a purpose is shown in the patent of L. M. Potts, No. 2,304,120 dated December 8, 1942. As will become apparent later in the description, in the present invention receipt of an all spacing signal by the five unit start-stop recorder causes the recording of an error indication character.

The invention contemplates the use of three basic mechanical apparatus units, a motor unit, a five to seven unit code conversion unit, and a seven to five unit code conversion unit. The motor unit is used for driving both converter units or a series of such units. The motor unit in addition to driving the converter unit also drives two sets of cams which may control various cam operated contacts according to the particular system in which the motor unit is used, Also included in the motor unit are several phasing and orienting devices which will be taken up later in the description.

The five to seven unit code conversion unit includes a single magnet selector which sets up the positions of a series of five unit code bars. The setting of the five unit code bar selects one of a plurality of character bars which establishes a selection for a series of seven unit code bars. 1 The selection of the seven unit code bars is in turn transferred to a series of seven gooseneck transmitting levers. Idle signals are automatically inserted to compensate for the gain of a seven unit transmitting cam sleeve, which continuously rotates, over afive unit start-stop selector sleeve. It should be mentioned at this time that in the seven unit radio system the idle signal contains marking impulses for the second, fifth and seventh elements of the code combination.

The seven to five unit conversion unit also includes a single magnet selector which. sets up the positions of a series of seven unit code bars; The setting of the seven unit code bars selects one of a plurality of characterbars, which establishes a selection for a series of five unit code bars. The setting of the five unit code bars is in turn transferred to a series of five gooseneck transmitting levers. When seven unit idle signals are received, the start-stop apparatus is not released so that no character will be printed by the five unit start-stop recorder at thi time. If no regular message character or no idle signal character is received, it is an indication that the ratio of three marking impulses to four spacing impulses in the code combination has not been maintained. At this time; the gooseneck transmitting levers will function to send an all spacing signal to the five unit start-stop recording apparatus and in response to the receipt of such a code combination an error indication will be recorded.

In one instance, the invention has been applied to a simplex radio system wherein the direction of transmission maybe changed by manual operation of a switch. For maintaining a phase relationship betweeen' a transmitting and a receiving station a tuning fork synchronizing arrangement is utilized, A further phasing arrangement included in this system consists of a finder mechanism which operates under the control of idle signals. The simplex radio system utilizes a motor unit, a five to seven unit code converter unit, and a seven to five unit code converter unit, located at each terminal of'the system.

The invention has also been applied to a one way, two channel multiplex system using interleaved signals. The transmitting terminal of this system is provided with two five toseven unit converter units while the receiving terminal is provided with two seven to five unit converter units.

A third system contemplated by the invention consists of a duplex radio system using a single frequency transmission band. This system is based on a time division method in which radio signals are transmitted in one direction for approximately one-half of a cycle and are transmitted in the opposite direction for approximately one-half of a cycle. Original signals are provided at opposite stations by any conventional five unit start-stop transmitter and are then converted into a seven unit code by means of a. five to seven unit converter unit. The seven unit signals are stored at each station and compressed into approximately one-half of a. transmitting cycle for transmission in alternate directions. Thus, while signals may be continuously generated by the seven unit transmitters at opposite stations, the signal code combinations pass over the frequency band on a time division basis. As-

the seven unit code signals are received, the code combinations are expanded to full cycle signals and are reconverted to five unit start-stop sig- 4 nals to operate conventional five unit start-stop recording apparatus.

A more comprehensive understanding of the invention may be had by reference to the following detailed description when read in conjunction with the drawings wherein:

Fig. 1 is a plan view of the motor unit;

Fig. 2 is a partial end view of the motor unit;

Fig. 3 is a detailed view of a portion of the motor unit particularly illustrating a cam sleeve orienting device;

Fig. 4 is a detailed view of a portion of the motor unit showing a finder mechanism;

Fig. 5 is adetailed view of a cam operated contact device. used inthe motor unit for synchronizing purposes;

Fig. 6 is a plan view of the five to seven unit code conversion unit;

Fig. 7 is a detailed view of a portion of a mechanism used for transmitting idle signal in the five to seven unit code conversion unit;

Fig. 8 is an enlarged detailed perspective View, partly exploded, of a mechanism used for delaying certain functional operations while idle signals are beingtransmitted;

Fig. 9 is a partial end view of the five to seven unit code conversion unit;

Fig. 10 is a detailed view of a part of the idle signal transmitting mechanism;

Fig. 11 is a detailed view, particularly illustrating the single magnet selector utilized in the five to seven unit conversion unit;

Fig. 12 is a detailed view of the character bar bail;

Fig. 13 is a detailed view of the five to seven unit conversion unit, particularly illustrating the mechanism used for storing and transferring seven unit codesignals.

Fig. 14 is a detailed view of the latching levers used for the seven unit transmitting levers and the idle signal transmitting levers;

Fig. 15 is a timing diagram of the operation of the five to seven unit code converter unit;

Fig. 16 is a plan view of the seven to five unit code converter unit;

Fig. 17 is a detailed view of the single magnet selector used with the seven to five unit code converter unit;

Fig. 18 is a partial detailed end view of the seven tofive unit converter unit;

Fig. 19 is a detailed view of a finder mechanism used with the seven to five unit code converter unit;

Fig. 20 is a detailed view' of the character bar operating ball of the same unit;

Fig; 21 is a partial detailed view of the mechanism utilized in the same unit for transmitting reconverted five unit start-stop signals;

Fig. 22 is a detailed view of a clutch operating mechanism used in the seven to five unit code converter unit;

Fig. 23 is a schematic circuit illustration of one system to which the invention is applied;

Fig; 24- is a schematic circuit illustration of a transmitting terminal;

Fig. 25 is a schematic circuit illustration of a receiving terminal of a secondsystem;

Figs. 26, 27, and 28 together constitutea schematic circuit illustration of a two way radio system used in the present invention;

Fig. 29 illustrates how the drawings should be placed in Figs. 26, 27, and 28; and

Fig; 30: is a timing diagram of the two way radio system;

With: particular reference. to Figs. 1 to 5, inelusive, the, motor; unit. contemplated by the present invention will first be described. Nu meral H represents the base of the unit, upon which is mounted a motor l2 which imparts rotary movement to shaft [3 and a gear |4 fixedly carried thereby. Gear I4 is in mesh with a gear l6 supported upon a hub H which is mounted about shaft |8 for relative movement with respect thereto. ment mechanism l9 (to be later described), gear I 6 drives the shaft 8 which is suitably; journaled on the vertically extending supports 2| and 22. Fast to shaft |8 are the gears 23 which are in mesh with gears 2-4, for the purpose of driving identical cam assemblies 26 as will later be described.

Carried on the hub H which supports gear I6 is a cam 21 which by means of pin and slot connections 28 supports a slidable escapement member 29. A spring 3|, attached at 32 to cam 21, and at 33 to escapement member 29, normally urges the escapement member in a downward direction as viewed in Fig. 4. Escapement member 29 is provided with a beveled camming projection 34 and with a driving projection 36 which engages the teeth of a ratchet 31 fixed to shaft I8 by means of a collar 38. Below shaft I8 is positioned a finder magnet 39 which controls armature 4| pivoted by means of lugs 42 on a fixed shaft 43. Armature 4| includes an upwardly extending arm 44 having beveled surfaces 46 and 41. A spring 48 normally urges armature 4| in a clockwise direction as viewed in Fig. 4.

In accomplishing a finding operation a key 49 is depressed while incoming idle signals are being received. If marking impulses are not received for th second, fifth and seventh impulses as will later be described in connection with the system operations, a relay 5| will be energized and a circuit will be completed through attracted contact tongue 52 for relay 53 which will lock up through its contact tongue 54 and contact pair 56. As contact tongue 51 is attracted, finder magnet 39 is energized and armature 4| moves counterclockwise. Cam 21 is provided with a groove 58, and as this groove presents itself to beveled projection 41 of arm 44 of armature 4|, the armature is free to pivot counterclockwise, and as it does so, beveled projection 46 carried by arm 44 engages beveled projection 34 of escapement member 29, camming the escapement member to the left as viewed in Fig. 4. As the escapement member snaps back to its original position on its continued rotation, driving projection 36 of the escapement mechanism will engage the next succeeding tooth of ratchet 31 so that a change in the driving relationship between gear l6 and shaft |8 has now taken place.

In other words, ratchet 31 has slipped back one tooth with respect to escapement member 29. As the armature 4| pivots counterclockwise as just explained above, its insulated tall 59 opens the contact pair 56 to break the locking circuit for relay 53. As long as the apparatus is out of phase with incoming idle signals, relay 5| will become energized and the ratchet 31 will slip back a tooth with respect to escapement member 29 in each rotation of gear l6. This presumes that the key 49 will be held down until a point will be reached whereat relay 5| will no longer energize and a circuit cannot be completed through contact tongue 52 for the operation of relay 53. This indicates that the idle signals are being properly received and that the apparatus has been brought into phase with remotely located apparatus.

By means of an escape- The operation of the escape-v ment mechanism |9 will be better understood when the system descriptions are later considered. The circuit shown in Fig. 4 is provided only for the purpose of illustrating the mechanical aspects of the operation of the escapement mechanism.

, Fixedly secured to shaft I8 is a cam 6| whose periphery is pursued by a follower 62 which is pivoted at 63. The number of lobes on the cam 6| may vary with the system in which the apparatus is used so that insulated tail 64 carried by the follower 62 may operate contact blade 66 back and forth between contact blades 61 and 68 a fixed number of times in each revolution of shaft l8. The contact blades 66, 61, and 68 are associated with a tuning fork phasing arrangement, the details of which will be described hereinafter in connection with the systems.

Returning now to the cam assemblies 26, a description of an orienting mechanism associated with each of said assemblies will be described. Cams 69 control contact pairs 1| at one side of each cam assembly while earns 12 control contact pairs 13 located at the opposite side of each cam assembly. Contact pairs 1 I, 13 are described here for the purpose of illustration but it will be understood that different numerals will be assigned to'the contact pairs shown in the system descriptions as will later appear. Gear 24 is fixed to a slidable shaft 14 mounted within a cam sleeve 84 and a sleeve 85 which are journaled on ball bearings 15, and 16. A coiled spring 11 urges the shaft 14 to the left as viewed in Fig. 3 by pressing against the interior of gear 24. Leftward movement of shaft 14 is adjustably restricted by means of a lever 18 pivoted at 19. For adjusting the position of shaft 14 a cup shaped dial member 8| is provided which is threaded upon the annular member 82 and the rim 83 of which bears against lever 18. Thus, by turning the dial member 8|, the position of shaft 14 will be adjusted and the relationship between the spiral driving gear 23 and the spiral driven gear 24 may be varied. Projecting through the cluster of earns 69, 12, which incidentally are supported on cam sleeve 84, is a dowel pin 86 which also projects through a collar 81 fixed to shaft 14. Thus, dowel pin 86 acts as a driving connection to rotate the cam assembly 26. Annular member 82 is provided with a pointer 86 for use in conjunction with the graduations 89 inscribed on the dial member 8|. Although the specific uses of the motor unit will be described later, it is now apparent that by operation of key 49 the apparatus may be brought into phase with distant apparatus. The orienting mechanism may adjust the apparatus so as to centralize the operation of contact pairs 1|, 13 with incoming signals.

With particular reference to Figs. 6 to 15, a description will now be given of the conversion unit which converts five unit start-stop signals into seven unit continuous signals. Numeral |-0| represents a base plate which supports a front wall I62 and a rear wall I83. Suitably mounted on walls I02, I03 by means of bearings L84, I86 is a shaft I01. A second shaft |08 extends between walls I02, I83 and is mounted on the bearings I89, I. Transverse to shafts 11, I68 there is supported on bearings H2, H3 a continuously rotating shaft I M which is suitably coupled toshaft |8 ofthe previously described motor unit. Carried by shaft 4 is a gear I Hi which is .in mesh with a gear||1 fast to shaft I81. Also carried by shaft H4 is a gear 8 which is in mesh with gear ||9 fast to shaft I08. "Thus, by the above described gearing ar- 

